#include <stdio.h>
#include <stdlib.h>

typedef struct student{
  char name [20];
  int id;
}student;

typedef struct node{
  student data;
  struct node *next;
}node;

void Push(node** headRef, student data){
  node * newNode = (node *) malloc(sizeof(node));
  if (!newNode) return;
  newNode->data = data;
  newNode->next = *headRef;
  *headRef = newNode;
}

node * readStds(char * filename){
  //first - we have to return the linked list of students, so we have to allocate it
  //        inside the heap so we avoid TAB-Victim problem
  
  //second- we do not really know the size of the elements to be read,
  //        so read and push one element at a time
  
  //third- we have to maintain the order of the students,
  //       so we push at the end
  
  node * head = NULL, **tailRef = &head;
  
  unsigned long ans, r = 0;
  student s; // I need one local variable
  
  
  //open the file
  FILE *f;
  if(!(f = fopen(filename, "rb"))) return NULL;
  
  while(1){
    if (fread(&s, sizeof s, 1, f) != 1) break;
    Push(tailRef, s);
    tailRef = &((*tailRef)->next);
  }
  
  //close the file
  ans = fclose(f);
  return head;
  
}

void printStudent(student s){
  printf("student [name = %s, id = %d ]\n", s.name, s.id);
}

void test(){
  char *fname = "students";
  int array_size = 0, i;
  
  node * head = readStds(fname), *current;
  for(current = head ; current ; current = current->next){
    printStudent(current->data);
  }
  
}
int main(void){
  test();
  return 0;
}